Function before form please. As long as it does it's job it'll do for me!

As far as I have seen during my communications with Kovid, I often get a reaction on ui changes like:
Not worth the effort for me, if you want to change it, I'm willing to support you by giving directions.

Main reason I get this reaction is because I want some small changes that will take a lot of time to implement. This, while Kovid wants to spend his time on functionality.

So Bricorn, I think you do not have to worry, the team has function on top of priority list. But if someone has the knowledge to changes the GUI, there are enough developers on the forum that can give directions.
So anyone who reads this treat, wants to help and is able to code in Python:
I'd suggest to contact Kovid and see if you can help. Or first download the source at launchpad and see if you're capable of changing the gui in a better way.

Spoiler:

While I'm not part of the development team, the information above is personal and not necessarily the philosophy of the development team. This is Just based on earlier communications with the team.

About the only criticism of the UI that I'd agree with is that it lacks graphical effects like shading/rounded corners/translucency etc on windows and OS X, which gives it a "outdated" appearance.

That is one that is valid, I think. I am entirely in favour of updating the UI to make it appear more "modern" in appearance, but I completely agree that it should not hinder functionality in any way. I love Calibre, and use it daily. Admittedly, I use no more than 25% of its functionality, but I can usually find the rest when/if I need it. And yes, I might choose a different set of icons, but again, that's a trivial change.

One thought that might answer some critics, and provide some folks with a chance to actually put their efforts where their mouths are, is to enable custom "skins". This could be as minimal as a set of icons, or get into other elements. Yes, it would require a fair amount of developmental effort to enable it, but would take the onus off for future UI changes.

(disclaimer: I am not a developer, and haven't looked at the Calibre source code. I have no idea how much work it would be to enable custom icons or skins.)

I read these UI threads and always come away shaking my head wondering what I'm missing. I seldom see any specifics about what changes need to be made to "make it more attractive." Is it all "shading" and "rounded corners on the boxes" type issues?

I do recognize that there are some confusing aspects of the UI that could be improved with coding effort. One lies in the multiple toolbars for "device connected," "device not connected," etc., but fixing these problem areas would seem to have limited payback. The problems mostly reside in the more obscure corners of Calibre (how many users change the toolbars?), and many current users have already learned the existing setup, so we're only talking about a subset of new users who would find it easier to find and learn these more obscure features. The gain due to reduced effort for these future users has to be balanced against the effort all the existing users would require to learn a new system, plus the effort to code up the "easier" interface.

I'd support such changes for anyone who wants to go to the effort, but I'd be even happier if they put that effort into new/better features.

Old (Joe Friday type) DOS guy here:
Just give me the facts . If I had to press a Key to launch a cover viewer, that would have been fine.
Calibre rocks in what it does.

Fully agree that calibre rocks. I'm a spoiled Mac guy spoiled by Apple for other OSs and types of interfaces, but calibre's UI doesn't bother me at all. Once I learned it I liked it. I don't need prettier icons, rounded corners, easier or simpler toolbars, or anything else mentioned in this thread except functionality. There are a few functional changes I'd like to see but I haven't bothered to make change requests so won't mention specifics here, plus I'm holding off hoping I'll have time to learn enough Python within some months to a year, and then practice some of that on calibre instead of asking for functional changes.

If a spoiled Mac person can live with the UI as is, and like it, anyone can….

The only problem with the gui I had was red red for adding and green for deleting. Those two colors just bug the hell out of me. So much so that I removed the delete button from my calibre toolbar now that I have changed the delete icon I have no problems with it.

To date I have only added one custom icon. It is a trash icon that jackie_w was kind enough to share. There are a few folks that have replaced all of their icons based on whatever theme their desktop used.

IMO, the main issues with the UI isn't any lacking beauty/animations (and please don't add any in case it slows down the program even more), it's the inconsitency. Let me explain:

By default, Calibre users mostly use/see the main toolbar and the context menu. However, I've found that there are several overlapping functions that appear in both the main toolbar and context menu, leading to confusion and waste of space. Every time I install Calibre I have to manually reconfigure the UI to my liking (I now don't even use the context menu). I wish there was a way to backup/transfer the UI settings to a new installation so I don't have to adjust/remember where all my UI preferences are.

Furthermore, is there an easier way to move/adjust the UI elements besides within the Preferences menu (preferably drag-n-drop, like Google Chrome, which is an epitome of UI design)? It's very tedious to have to use the Up/Down/Left/Right arrows to move the icons around within the toolbar and context menu.

Every time I install Calibre I have to manually reconfigure the UI to my liking (I now don't even use the context menu). I wish there was a way to backup/transfer the UI settings to a new installation so I don't have to adjust/remember where all my UI preferences are.

I've used calibre for three years and (while not guaranteed by Kovid) I've been very successful copying my old config to my new install/computer. My menus and toolbars seem to work and if I recall correctly plugins might need to be added again but the plugin configurations often remain.

I agree with both the original poster (and other drivers for improvement) and the apologist of the status quo.
Calibre is a useful, powerful, feature rich application as it is AND at the same time it definitely could use some serious usability overhaul. As good as Kovid and other developers are, they are programmers and that fact alone makes them less than ideal interaction designers. Also Calibre is being developed using Piece Meal Grows pattern and it does not really lend itself to easily creating great usability.

If any of you are really interested in this subject and want to improve Calibre, find and read these two books. You will understand what USABILITY and Interaction Design really means. How and why some things excel at it and some are just meh (Calibre) and some really suck at it.

"The Design of Everyday Things" by Donald Norman (father of usability as field of expertise). You will look at the world around you, especially at manmade things with different eyes, forever. I could not put it down - read it in one day.
and"The Inmates Are Running the Asylum: Why High Tech Products Drive Us Crazy and How to Restore the Sanity" by Alan Cooper
And you will see why developers are at disadvantage when creating good interfaces. It's not their fault. In this book Alan (one of the most prominent figures in interaction design) describes two kinds of humans: Homo Sapiens (normal people) and Homo Logicus (developers etc) and the differences between these two species. Their needs & priorities when using software and their behavioral patterns when dealing with the other kind.

Come back to this thread after you've read this book particular, you will understand all view points but ... you'll see

These gems are really fun to read and will truly change your lives - especially if you are developer with ambition to write great programs rather than just useful.

About the only criticism of the UI that I'd agree with is that it lacks graphical effects like shading/rounded corners/translucency etc on windows and OS X, which gives it a "outdated" appearance.

This. Plus the "grid style" or "shelf style" cover browser that has been in the works for over a year now, according to Kovid. I agree - the interface needs updating. I even looked at starting to work on it, before I realized that the main UI is done in Python and I have no clue when it comes to programming Python.

That being said - the program does what it is supposed to do and does it very well. Would I like it prettier? Well, sure. (I'm female, we're odd like that, or most of us are, anyway). But absolutely NOT at the cost of functionality, and not if it takes away time from improving/refining that functionality.

Apparently, what we need is a talented person who does UI design and does it in Python, and can also do it without ruining the functionality of the program. Oh, and works for free. Anyone got anyone like that hiding up their sleeves?

I've used calibre for three years and (while not guaranteed by Kovid) I've been very successful copying my old config to my new install/computer. My menus and toolbars seem to work and if I recall correctly plugins might need to be added again but the plugin configurations often remain.

Would you mind sharing how to do this? Also does this save just the UI config or all the preferences data?

Would you mind sharing how to do this? Also does this save just the UI config or all the preferences data?

All preferences are stored here.

Go to Preferences - Miscellaneous and Open calibre configuration directory. This is the directory with the configuration. Assuming the same OS, move it to replace the new install's config directory, start the new install and keep your fingers crossed. If for some reason it screws thing up exit calibre and delete the directory, upon starting calibre a default config will be recreated.

If you run the portable version this should work every time.

A preferences backup feature to guarantee moving preferences between installs would be nice. I just use the portable version now and the same exact setup works on my Windows 7 and Windows XP machines.